How do you adjust levothyroxine if TSH is high?

In this article:

• Adjusting levothyroxine to lower TSH
• What to do if levothyroxine is not working
• Causes and symptoms of high TSH

In this article

• Adjusting levothyroxine to lower TSH
• What to do if levothyroxine is not working
• Causes and symptoms of high TSH

If you are taking levothyroxine and notice an elevated TSH on your blood test report, you are right to wonder if something needs to be changed. TSH stands for thyroid-stimulating hormone and is produced by the pituitary gland, which sits at the base of the brain.

The pituitary gland senses whether there is not enough thyroid hormone circulating in the bloodstream. If there is not enough, the pituitary makes more TSH to tell our thyroid gland to work harder, so your TSH could be high if you do not have enough thyroid hormone. 

Levothyroxine is a supplemental thyroid hormone medication that can help. When and how to adjust levothyroxine in the setting of a high TSH are not simple. Get the medical advice of your healthcare provider to determine your next step, but it can be helpful to understand some of the concepts.

Steps to adjust levothyroxine if TSH (thyroid stimulating hormone) is high

When you consult your healthcare provider about your elevated TSH, they may discuss or ask you about the following:

1. How to take levothyroxine
2. This drug is selective in how it is absorbed. If you take it too soon after eating or eat too soon after taking it, the food in your stomach can reduce how well it is absorbed. Therefore, it is recommended that people take levothyroxine at least 30 to 60 minutes before eating breakfast or at least two hours after eating their last meal of the day. If not, too little levothyroxine could be absorbed, lowering your thyroid hormone and causing your TSH to be too high.
3. Possible interactions with currently prescribed medications 
4. The absorption of levothyroxine can be blocked by other medications that negatively interact with it. Bile acid sequestrants like Questran (cholestyramine), iron supplements, and calcium supplements are the biggest offenders. Your multivitamin could be the problem, based on its iron and calcium components. Among the other possible offenders, common medications like the heartburn pill Prilosec (omeprazole) and antidepressant Zoloft (sertraline) can cause problems. Any drugs that reduce the absorption of levothyroxine should be separated from the thyroid hormone’s dosing by a few hours.
5. Contributing factors that can affect dosing
6. Hypothyroidism commonly occurs due to Hashimoto’s thyroiditis, an autoimmune condition in which our immune system slowly attacks the thyroid. Among other causes, hypothyroidism can also be iatrogenic, meaning it is caused by medical treatment, such as radiation treatment or removal due to thyroid cancer. Your cause of hypothyroidism, as well as your size and age, contribute to what dose of levothyroxine you will need to be euthyroid or well-balanced.
7. How long you have been taking this dose of levothyroxine 
8. When thyroid hormone replacement is first started, it can take at least six weeks until a steady state level is reached. A TSH checked any sooner than four weeks after beginning levothyroxine may not truly reflect whether the dose of levothyroxine is adequate. Likewise, when the levothyroxine dose changes, a repeat TSH level is usually not done for another four to eight weeks.
9. If the manufacturer of your levothyroxine has changed
10. Levothyroxine is a generic prescription drug, and there are multiple manufacturers. Pharmacies sometimes change which company supplies their generic levothyroxine. The U.S. Food and Drug Administration (FDA) expects dose equivalency between generic manufacturers. Findings from a clinical study agree with the FDA, but some medical providers advise patients to remain on the same manufacturer’s generic or brand-name version. Generics should be equivalent to Synthroid, Unithroid, Levoxyl, or Euthyrox. SingleCare’s coupons or discount card can help reduce costs if a brand name is necessary.
11. Details of TSH level 
12. Experts still debate what constitutes a normal TSH level. Generally, a TSH between 0.5 and 4.5 mU/L is considered normal, but some labs may define it differently. If a patient’s TSH is flagged by the lab as abnormal at 4.0 mU/L, for instance, a doctor may or may not feel it is necessary to increase the levothyroxine dose.
13. Free thyroxine or free T4 levels
14. This is a measure of your actual circulating thyroid hormone. It is a critical blood test when first diagnosing hypothyroidism. A high TSH and low free T4 are the classic findings of primary hypothyroidism. On the other hand, a mildly elevated TSH with a normal free T4 probably represents subclinical hypothyroidism, a condition that usually needs to be monitored but not treated. Once hypothyroidism is diagnosed and treatment begins, TSH is commonly checked on its own.
15. Medical conditions
16. If your healthcare provider determines after their analysis that your levothyroxine needs to be changed due to a high TSH level, they may increase your dosage. The amount of the change may depend on your age and health conditions, namely any heart disease or heart arrhythmias. Starting with too high of a dose or increasing too quickly could increase the heart rate and provoke a problem, particularly among seniors and those with heart conditions.

An initial levothyroxine dosage is set by a healthcare professional, either a primary care provider or endocrinologist, based on factors like your particular thyroid condition, body weight, age, and other medical problems. Once the drug is begun, the American Association of Clinical Endocrinologists and the American Thyroid Association recommend rechecking a TSH in four to eight weeks, although sometimes sooner if circumstances warrant. After a levothyroxine dose change, TSH is again typically checked in four to eight weeks. Pregnancy can lead to different dosing and monitoring schedules.

When a TSH level in the normal range is established and stable, levels are sometimes only tested every six to 12 months. A normal TSH level correlates with your feeling of returning to yourself. Fatigue, weight gain, and hair loss could be experienced if your TSH is high, meaning your levothyroxine dose is too low. On the other hand, if your TSH is low because of a high levothyroxine dose, you could experience shakiness, heart racing, or diarrhea. Your doctor will determine how to address any symptoms and how often to monitor your TSH.

What should I do if my TSH levels remain high despite taking levothyroxine?

It can be frustrating to see your TSH remain elevated despite taking levothyroxine. Sit down with your healthcare team and discuss the matter. They will go through the steps of questioning how you are taking the drug, examining what other prescription and over-the-counter medications you take, and how long you have been on your current dose. Suppose your medical provider feels that you have been taking levothyroxine correctly, without interfering with foods or other medications, and at an appropriate dose. In that case, they might look into other causes of levothyroxine malabsorption. For example, celiac disease or gluten sensitivity can reduce how well levothyroxine is absorbed.

Common causes and symptoms that your TSH is too high

A TSH that is too high in conjunction with a free thyroxine that is low can be associated with symptoms of hypothyroidism, such as the following in adults:

• Fatigue
• Weight gain
• Constipation
• Slowed thinking or movement
• Intolerance to cold temperatures
• Depression
• Joint and muscle pains
• Irregular periods
• Dry skin
• Hoarse voice
• Leg swelling
• Eye swelling
• Bradycardia (slow heart rate)

Common causes of a newly discovered high TSH include subclinical and overt hypothyroidism caused by autoimmune thyroiditis, radiation damage, and surgery. Suppose a diagnosis of hypothyroidism is already in place, and levothyroxine therapy is ongoing. In that case, a high TSH is typically either from not taking the levothyroxine correctly or not having a high enough dose. Dose increases are done slowly, carefully, and under the direction of a healthcare professional to get you back to feeling your best.